#16 What is Legionella and how is it controlled in DHW systems? (with Kevin Freidt)

Greg and Dan welcome Kevin Freidt, Caleffi Director Product Management & Technical Support (a..k.a. The Dr. of Disinfection) to the microphone.  They explore the fascinating topic of Legionella bacteria and its impact in domestic hot water systems.  Kevin starts with "bug basics":  where does the bacteria originate, when is it dangerous, what causes it to proliferate and how is it contained?  He discusses dead legs in potable water piping systems and explains how water becomes "old."  Not familiar with the ASHRAE 188 Standard?  Take note!  It's an important reference guide.  The Ask Caleffi Team completes this podcast with an interesting discussion on how we can ensure safety in our water systems.

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Transcript

00:00

[Music]

00:05

welcome to ask Caleffi the podcast that

00:08

dives into real life problems that

00:10

plumbing and hvac technicians face in

00:12

the field we're your hosts from the

00:14

Caleffi tech support team i'm greg tubbs

00:16

and i'm dan firkis welcome we look

00:19

forward to sharing some stories from our

00:20

tech calls and using our background and

00:22

expertise to make your days a little

00:24

easier

00:25

[Music]

00:30

there welcome back uh we're going to

00:32

talk about some legionella in domestic

00:34

hot water today how are you doing dan

00:36

we're doing good how are you oh can't

00:38

complain what have you been up to lately

00:40

outside of work oh not a whole lot a lot

00:42

of yard work yard work yeah a lot of

00:44

yard work no fishing a little bit of

00:46

fishing okay good yeah you got to do a

00:48

little bit of fishing to keep yourself

00:50

sane every once in a while unfortunately

00:52

more yard work than fishing yeah you're

00:53

gonna have to change that right

00:57

so

00:58

we have a guest speaker for today we do

01:00

we're excited yeah we have kevin fried

01:03

he's our director of product management

01:05

and tech support here at calefi yeah i

01:07

think you were saying he's like the

01:09

stella of legionella he's the doctor of

01:11

disinfection

01:12

[Applause]

01:15

welcome kevin wow it's hard to follow

01:17

that

01:18

[Laughter]

01:21

so

01:22

i mean we hear a lot about

01:24

legionella and legionella control in our

01:26

industry um i mean

01:29

every so often an article comes up of a

01:31

hotel or

01:33

a regional hospital or something yeah

01:35

something out there that they have a big

01:38

legionella breakout yeah yeah yeah we're

01:41

hearing a lot about it uh it's something

01:43

that's been around forever i mean you

01:45

start from the basics right it's a

01:46

bacteria that's everywhere all around us

01:49

it's in the lakes and streams in the

01:50

water

01:51

uh in in uh even in the building

01:54

plumbing system the premise plumbing

01:56

that bacteria gets in there from the

01:58

municipalities or from the wells right

02:00

and you know generally that bacteria

02:02

isn't a problem you can drink that water

02:04

and it'll go through your body and it

02:06

doesn't harm you it's only a problem

02:08

when that bacteria gets really

02:09

concentrated and then gets into your

02:11

lungs right yeah it gets airborne

02:13

doesn't it right it likes to be um warm

02:16

and and moist and have oxygen and some

02:19

food and your lungs are a perfect

02:20

environment for that right absolutely

02:23

what i'm going to play the dumb guy and

02:25

ask some questions i can do that pretty

02:26

well

02:27

so what are the ideal temperatures for

02:30

legionella to really flourish and and

02:33

grow

02:34

well room temperature really anywhere

02:36

from say 70 to 120 degrees

02:39

and you know that's that's water that's

02:42

sitting in a pipe in a building is going

02:43

to be at that temperature if it's not

02:45

moving

02:46

and if there is some

02:48

corrosion in that pipe or a biofilm and

02:51

a little bit of oxygen that legionella

02:53

is perfectly happy there it's a great

02:54

place to raise a family and proliferate

02:57

and uh if it gets really concentrated

02:59

that's when it can be a problem right so

03:01

maybe a dead leg in a building where you

03:03

know recirc line isn't moving that water

03:05

through is a exactly kind of a good

03:07

environment for that

03:09

bacteria to grow would you say

03:11

legionella probably thrives at that

03:13

higher temperature it really

03:16

grows and gets stronger through

03:19

in that higher temperature that 120. any

03:21

anywhere within that range really if you

03:23

have cold water like water below 60

03:26

degrees

03:27

the bacteria is still there but it won't

03:28

grow it won't it's dormant and anything

03:32

above 122

03:34

clinically speaking will start to kill

03:36

it so the higher temperature will

03:39

begin to kill that legionella so if you

03:41

get up to 130 or 140 then you start to

03:44

kill that bacteria

03:45

and the higher temperatures will kill it

03:47

faster okay yeah i was kind of looking

03:49

at it and it looked like that 70 to 110

03:52

degree range was really a kind of a hot

03:54

spot where that bacteria really grows

03:57

exactly

03:58

how does someone get legionella out of

04:00

plumbing i mean obviously you say it it

04:03

can grow well in our lungs so i think

04:04

that's a good

04:05

segue into where it's how you can get it

04:09

yeah it almost have to become airborne

04:11

so i would assume maybe like in a shower

04:13

or yeah in fact if you go back to where

04:15

the name came from the legionnaires

04:17

disease was

04:19

uh it was named after a 1976

04:21

legionnaires convention in philadelphia

04:23

and what happened there was they had a

04:26

cooling tower that was really infected

04:27

with the bacteria and that cooling tower

04:29

was spewing that bacteria outside and it

04:31

was blowing all around the city and a

04:34

lot of people got sick from that and but

04:37

prior to that we didn't really

04:38

understand what what the whole issue was

04:41

but that's kind of the beginning of it

04:42

all 1976 and so now we know a lot about

04:46

it we know how it grows how it

04:48

proliferates

04:50

how it can make people sick we have

04:51

specific tests for it now

04:54

and we know a lot more about it than we

04:56

ever did right well we're starting to

04:58

see a lot more um guidelines put in

05:00

place or standards put in place for

05:02

legionella control in buildings right

05:05

and cooling towers are only one way to

05:06

aerosolize the bacteria or the water

05:09

droplets right sure so if you have a

05:12

spa or a water fountain in a hotel or in

05:16

your shower of course these are other

05:18

ways that you can get water droplets

05:20

into your lungs right so if there is a

05:22

high concentration of bacteria in any of

05:24

those water droplets you can get sick

05:26

and there are a lot of documented cases

05:28

from

05:29

water decoration features in the lobby

05:31

of hotel for example

05:33

and it's especially dangerous when you

05:35

have

05:36

people that are

05:37

susceptible to disease like if you have

05:40

an elderly facility or

05:42

a place where there are cancer patients

05:45

or people that are really prone to

05:47

getting sick easily it doesn't take much

05:49

and so that's why we see some outbreaks

05:51

in healthcare facilities

05:54

schools hotels

05:56

you know greg you mentioned a hotelier

05:57

in atlanta a hotel had to shut down for

06:00

right i think a number of weeks because

06:02

of that and it was a few people got sick

06:05

and even died from that so that's the

06:07

issue when it gets into your lungs yeah

06:09

it's interesting i when i think of

06:11

legionella because you know we're in the

06:13

plumbing business plumbing product

06:14

business

06:16

i think about it strictly with domestic

06:18

hot water and plumbing but you're right

06:20

like a water feature

06:22

yeah any place where there's old

06:24

stagnant water that just it's kind of

06:25

being slowly recycled and never really

06:28

flushed out or moved around right you

06:30

think of like a fountain where they're

06:31

moving that water and the droplets are

06:33

becoming airborne i mean i suppose that

06:35

could be inhaled and

06:37

right and be a concern and those those

06:39

features like the water fountain or or

06:41

even a hot tub you know those are

06:43

treated with chemicals right

06:45

but in the you mentioned the domestic

06:47

hot water recirculation that's

06:49

you know that's water that goes to our

06:51

sinks and our faucets and our showers

06:53

and that's that's where we need to be

06:55

particularly careful as you know

06:57

plumbing professionals right i think

06:59

with the

07:00

with the lockdown that we just came out

07:02

of with the whole covet you had a lot of

07:04

buildings sitting

07:05

you know not being used with domestic

07:07

water systems not being used i mean i

07:09

think you know we i know we focused

07:12

pretty heavily on on how to start those

07:14

buildings back up and bring them back

07:15

online right right what can happen is

07:17

that when that water let's say it comes

07:19

from the municipality and it might be

07:21

treated with monochloramine well that

07:23

that monochloramine degrades over time

07:25

so by the time that water

07:27

gets to the building it's gone through

07:29

some piping and you know some some

07:31

probably some corroded pipes and it got

07:33

warm

07:34

and the

07:35

the effectiveness of that monochloramine

07:38

is limited so once that water gets to

07:40

the building there may or may not be

07:42

much protection left

07:43

and if it sits in the building for a

07:45

while then it gets old the

07:46

monochloramine is basically gone right

07:49

and then if you have those conditions we

07:51

talked about earlier that's when it gets

07:53

dangerous so what we need to do as

07:55

plumbers we need to understand that dead

07:58

legs and that and that's a piece of

08:00

piping in in the potable water system

08:02

that doesn't have movement

08:04

or

08:05

any any time water gets old right and

08:07

how does the water get old well we have

08:09

now these very efficient fixtures right

08:11

our showers are very low flow and we've

08:13

been conserving water since the 90s

08:16

right we always thought well that's

08:17

really important to conserve the water

08:19

well there's another way to look at that

08:21

now you're conserving water but what are

08:22

you doing you're making that water older

08:25

so that water might get to your

08:26

commercial building and spend you know i

08:28

don't know a week or two weeks in the

08:30

piping and rather than being flushed out

08:33

when you're using a lot of water and

08:34

sending it down the drain that water now

08:36

becomes dangerous sure

08:38

yeah i suppose it's sitting in the pipes

08:40

longer it's so it's also cooling off too

08:42

by cooling off or warming up even the

08:45

cold water you know if you have the cold

08:46

water coming in and then it sits in some

08:48

piping and a plenum somewhere that water

08:50

will easily get to 70 75 degrees yeah

08:53

it's not going to retain its its cold

08:55

ground temperature of you know 50 or 48

08:58

degrees it's it's sitting now in room

09:00

temperature air and through conduction

09:03

it's it's warming up it grows into an

09:05

unsafe state right right and that's

09:08

generally a bigger problem in commercial

09:09

applications because in our homes we

09:12

don't really need to worry about it too

09:13

much because each of us use

09:15

what 80 or 100 gallons a day on average

09:17

and so we're using all the water in our

09:19

house every day so unless you have a big

09:21

lake house like greg does up in the

09:23

north woods

09:24

and he goes up there you know every

09:27

every month or two right you know so

09:28

when you get there you need to flush all

09:30

that water out of there greg don't don't

09:31

take a shower unless you've

09:34

replenished all that i have a lake house

09:35

that i don't even know about

09:38

you guys have been going there haven't

09:39

you well when you find it greg take us

09:41

along

09:42

so we get that question sometimes what

09:44

about residential typically it's not a

09:46

problem cool

09:47

what can we do to keep people safe i

09:49

think we kind of touched on that but i'm

09:51

going to ask that question anyway well

09:53

we can all do something the designers

09:55

you know the folks that are the

09:56

engineers that are designing our piping

09:58

systems they need to worry about

10:00

making sure that we don't have piping

10:02

sections that will harbor

10:05

old water right so design around

10:08

no dead legs

10:10

as as an installer we can make sure that

10:12

we keep our piping clean that we do a

10:15

really good flush we want to keep the

10:17

pipes as

10:19

clean as we can to minimize corrosion

10:21

and biofilm

10:23

and as as a practitioner you know as a

10:24

service person just remember that

10:27

flushing is important you know flushing

10:29

don't don't worry so much about flushing

10:32

water when you're in a building where

10:34

there are people that can get sick if

10:35

they get some of this bacteria in their

10:37

lungs

10:38

so right you can turn that water on

10:40

flush that system keep that water moving

10:42

exactly and there are some really good

10:44

materials out there to read ashrae

10:46

guideline 188 is great

10:48

it talks about water management plan so

10:51

that that guideline is meant for

10:53

everyone from the designers to the

10:54

building users and it talks about safe

10:56

practices and what you can do to

10:58

minimize the the risk of legionella

11:00

disease

11:02

and

11:03

so it defines the water management plan

11:05

doesn't really tell you what to do

11:07

it just says you need to have a team

11:08

that's responsible uh you need to have

11:11

records of what's going on stuff like

11:13

that

11:14

sure so

11:16

in an ideal situation perfect world

11:18

scenario

11:20

if were you designing a system

11:22

you know what would you include in in

11:24

your plan

11:26

to

11:26

try and

11:28

manage this you know manage legionella

11:30

control

11:32

well if you can keep the hot water hot

11:34

okay make sure it's the piping is

11:36

insulated keep it above 122. when you're

11:39

if you're designing a recirculation

11:41

system which we all see in commercial

11:43

yeah don't let that water anywhere in

11:45

that loop get below 120 too even on the

11:48

return leg coming back if that water

11:49

comes back at 90 degrees then that

11:52

section of the piping is dangerous so

11:54

make sure that you have high temperature

11:56

storage store your water at 140 or more

11:58

or if you have an instantaneous system

12:00

you know deliver it at 140 or more mix

12:03

it down if you need to

12:05

to make it safe but don't let it get too

12:07

cool that's on the hot water side

12:09

and that's really where we play where

12:11

khalefi place is on that hot water side

12:13

on the cold water side that's kind of a

12:15

different deal you need to have some way

12:18

of flushing everything

12:19

periodically to keep the bacteria down i

12:22

know in talking at one point um when we

12:25

talked about water quality in a building

12:27

isn't there some liability that falls

12:29

back on the owner of that building you

12:31

know if you if you looked at like a

12:32

hospital or a multi-family unit to to

12:35

insure

12:36

i thought there was some liability that

12:38

fell back on the owner to make sure that

12:40

that water was safe

12:42

if the building owner or manager adds

12:44

chemicals on their property then they

12:47

take ownership of that water system so

12:49

that's really important to know so if

12:51

you're going to put in a

12:54

chlorine additives or something else to

12:56

treat the municipal water after it gets

12:58

into your building you need to be very

13:00

uh aware of that okay so that's that's

13:02

where thermal disinfection um would be a

13:06

safer

13:07

safer route

13:08

of killing the water without using

13:10

chemicals right when it comes to the

13:12

the recirculation system that's where we

13:15

play right that's our that's our

13:17

business

13:18

we want to make sure that we always have

13:20

water above 122 in that whole system

13:23

don't turn off your recirc pump keep the

13:25

water moving right that that minimizes

13:27

stagnation

13:28

and then um employ what's called thermal

13:31

disinfection and we have a product that

13:34

does this it's an electronic mixing

13:36

valve that will periodically and

13:37

regularly automatically raise the

13:40

temperature in that research system to a

13:43

level that will kill the bacteria and

13:44

you can do this for example every night

13:46

have the research water go from say

13:49

130 up to 150 for 60 minutes for example

13:54

and then that part of the piping

13:56

whatever whatever that water is

13:57

circulating that will

14:00

have legionella control just by using

14:02

temperature so there's no chemicals

14:04

involved and they've been doing this in

14:06

europe for many many years it's not all

14:08

that popular here in the us but we're

14:10

trying to educate people on how that

14:12

works it's a very effective thing to do

14:14

it's very safe and if you already have a

14:16

master mixing valve you're not adding

14:18

any costs to the project so there's no

14:21

chemicals involved

14:22

you just raise the temperature every

14:24

night set it back down to normal and the

14:26

number one question that always comes up

14:28

is oh gosh we're going to have scalding

14:30

water going through this system right

14:32

now

14:33

the most the most important thing to

14:35

know if you're going to do this is to

14:37

have anti-scald valves everywhere at

14:39

every fixture and if you have those asse

14:42

1016 shower valves if you have the asse

14:45

1070 anti-skull valves at all your

14:47

janitor sinks or any point of use you

14:49

can do this safely it's not a problem

14:52

right you're protected at the point of

14:54

use right yeah nobody's going to get

14:55

sick and you just if you raise those

14:57

temperatures for an hour every night and

14:58

set them back to normal uh it's actually

15:01

a very uh efficient and effective way to

15:03

control the legionella

15:05

absolutely yeah and and less liability

15:08

for a building owner right you're not

15:09

adding chemical chemicals and the the

15:12

legiomix valve that we sell uh has a

15:14

built-in data logger so the building

15:16

owner the manager has records so they

15:19

have a recorded record a database of the

15:21

temperatures and what they've done so

15:23

they have records that they can show to

15:26

someone if they ever have to

15:28

and if you know it that's a way of

15:30

meeting some of the requirements of

15:32

ashrae 188 to make sure you document

15:34

what you have

15:35

right so that protects uh the owners or

15:38

who's ever responsible from potential

15:40

you know lawsuits or liabilities anyway

15:43

having the having some record of what

15:45

you've been doing it's very helpful to

15:47

have that that

15:49

added benefit with that product it

15:51

certainly is well i think we covered

15:53

this topic really well yeah

15:56

any closing final thoughts on it

15:58

no i mean there's a lot to talk about i

16:00

mean i

16:01

i like talking about it as you can tell

16:03

and there's a lot of great information

16:05

we can help you anybody who is

16:06

interested just give us a call here at

16:08

calafi we have

16:10

some really good references our

16:11

hydronics technical journals talk about

16:14

it we have

16:16

magazine articles that talk about it and

16:17

we'll be

16:18

more than happy to help anyone with uh

16:21

with information uh on this topic yeah

16:23

we'll certainly be have more information

16:25

to come in the future

16:26

absolutely that's it for now yeah thanks

16:29

guys thank you thank you

16:31

thank you for tuning in if you ever need

16:33

help please feel free to contact our

16:35

tech support team anytime at

16:37

techsupport.us

16:40

caleffi.com

16:42

or call us during our business hours at

16:44

7 30 a.m to 4 30 p.m

16:48

central time

16:49

at 414-238-2360

16:54

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